Derelict (i.e., lost or abandoned) commercial fishing gear, including nets and traps, can present safety, nuisance, and environmental impacts in freshwater, estuarine, and marine waters. Fishing gear can become derelict for a number of reasons, e.g., buoy lines can be severed by vessel propellers or break due to age, buoy materials can fail, storms can roll the traps pulling the buoy below the surface, and traps can be vandalized or abandoned.
The quantity of derelict fishing gear in the nation's estuaries and coasts is unknown. In a pilot study in Virginia, the density of derelict pots in a specific crab fishing sector was determined to be about one pot per 12 acres (Havens, K. J., et al. “The effects of derelict blue crab traps on marine organisms in the lower York River, Virginia”, North American Journal of Fisheries Management (2008), 28, pp. 1194-1200). It has been suggested that 250,000 derelict crab traps are added to the Gulf of Mexico annually, based on an estimated 25% loss/abandonment rate and an annual total number of traps fished commercially of approximately 1 million. The Gulf States Marine Fisheries Commission has estimated blue crab derelict fishery losses of as high as 4 to 10 million crabs a year in Louisiana (Guillory, V., et al., Proceedings: Blue Crab Mortality Symposium, Gulf State Marine Fisheries Commission (2001) Ocean Springs, MS, pp. 28-41). For more information related to the quantity of derelict gear, see Example 1.
Derelict fishing gear damages sensitive habitats and continues to capture both target and by-catch species, a process known as “ghost fishing”, leading to reduced fitness and delayed mortalities of aquatic species. Beyond ghost fishing, the derelict fishing gear can break apart, causing massive amounts of non-biodegradable material to enter the aquatic ecosystem.
The effect of derelict fishing gear is significant, and various states and regions have enacted measures to reduce the ecological and economic impacts of abandoned equipment. The emphasis thus far has been on ghost fishing. For example, the state of Florida enacted regulations (CH 46-45, F.A.C., effective Jan. 1, 1995) establishing degradability requirements for blue crab traps. Traps are considered legal in Florida if a non-degradable trap lid (such as a metal panel) is secured to the trap using degradable materials such as jute twine or corrodible hooks. Since the focus is on ghost fishing, these regulations fail to regulate the significant amount of aquatic debris created by derelict fishing gear each year.
Compounding the problem is the use of non-degradable plastic components. For instance, various components such as trap lids and identification tags made of plastic can detach from derelict fishing gear. Once disengaged, the buoyancy of plastic causes the debris to float and ocean currents can deposit plastic on foreign coasts. It is a common occurrence for fishing gear components originating in the United States to end up across the Atlantic Ocean in the United Kingdom and Ireland. These non-degradable plastic components remain largely intact despite spending years afloat, and therefore can be easily traced to the issuing state. Furthermore, plastics can themselves be toxic or can absorb toxic pollutants, and can be considered hazardous waste. Therefore, the transportation of plastic materials raises both ecological and political issues concerning proper stewardship.
There remains a need for an improved identification component that degrades quickly in an aquatic environment after fishing gear becomes derelict. Ideally, any such implementation would not degrade significantly while being actively fished, but degrade within a period of time after the fishing gear becomes derelict. We have identified a degradable plastic, polyhydroxyalkanoate (PHA), as an exceptional material for such purposes. The present invention modifies existing identification components with a novel degradable polymer that breaks down into benign constituents. To reduce the economic burden on fishermen, it would be advantageous if the degradable identification components could be inexpensively substituted for existing systems of identification, thereby providing the desired degradability without requiring the purchase of expensive new equipment.